When the polycyclic alumosiloxane [Ph2SiO]8[AlO(OH)]4is allowed to react with either cyclopentadienyl sodium in tetrahydrofuran or with dimethyl zinc in diethyl ether the organic ligands on the metal elements are eliminated as cyclopentadiene or methane and the metals are bonded to oxygen atoms in the alumosiloxane forming [Ph2SiO]8[AlO2(Na)]4∙5(THF) or [Ph2SiO]8[AlO(OH)]2[AlO2]2[Zn(OH)]2∙2(OEt2), respectively. X-ray structure determinations reveal that in the sodium derivative the original polycycle rests almost unchanged while in the zinc derivative the inner skeleton is rearranged.